Opus to MP3 Converter for WhatsApp Voice Notes

Convert a voice note in three steps

1. Get the voice note onto your device as a file (see below), then open it with the box above.
2. Keep 128 kbps; voice notes are speech and gain nothing from more.
3. Convert and save the MP3.

Getting the file out of WhatsApp

On Android, long-press the voice note, tap Share and save it to Files or Drive, or find it in your phone's file manager under the WhatsApp media folder for voice notes. On an iPhone, long-press the voice note, tap Forward, then the share icon, and choose "Save to Files". Exporting a chat with media also includes the voice notes as separate files. In every case you end up with a file ending in .opus, or sometimes .ogg, and either works here.

What Opus is

Opus is an open audio codec designed for voice calls and streaming. It sounds clear at very low bitrates, which is why WhatsApp uses it to keep voice notes small. The file is Opus sound in an Ogg container. MP3 is older and less efficient, so the MP3 will be bigger than the voice note, but it plays on everything, from car stereos to email attachments on any computer. More detail is in the Opus codec article.

Privacy

Voice notes are often personal, and sometimes they are evidence. Uploading them to a random converter site puts a copy on someone else's server. Here, the open-source ffmpeg engine runs inside your browser tab: the file is read from your device and the MP3 is written back to it, with nothing sent anywhere.

Turning voice notes into text

Once it's an MP3, a voice note can be transcribed with mydubly's audio to text tool, with timestamps, in 21 languages. Upload the MP3 rather than the .opus file. A transcript costs 1 credit per minute with a 5-credit minimum per file, and new accounts start with 100 free credits. For a voice note in a language you don't speak, the audio translator returns the text and a voice in your language.

How the free converter works

The converter is ffmpeg, the open-source media toolkit, compiled to WebAssembly so it runs inside your browser tab. Your file is read straight from your disk by that engine; it is never uploaded to mydubly or anywhere else, and no account is needed.

• The engine is about 30 MB and downloads the first time you convert something. After that your browser normally keeps it.
• Large inputs are fine because the file is read in place, but the result is built in memory, so outputs are capped at about 1.5 GB.
• Speed depends on your device. Copying streams takes seconds; re-encoding video is the slow case.
• Keep the tab open until the download button appears. Closing it stops the conversion.